Method and apparatus for providing bus protocol simulation

ABSTRACT

A method and apparatus for providing bus protocol simulation in a multi-processor data processing system (10). A plurality of edge interface circuits (14,16) are used to interface a first bus (32, 34, 36), which uses a first bus protocol, with a plurality of data processors (50-65), each of which uses a second bus protocol. A memory (90) within each edge interface circuit (14,16) is loaded with a plurality of values. Each of the plurality of values has a control portion and a data portion. The control portion of memory entry &#34;N&#34; is used to initiate the transfer of the data from memory entry &#34;N+1&#34;. In an alternate embodiment, multi-processor data processing system (210) includes a plurality of data processors (250-258) and a plurality of edge interface circuits (214-217).

This application is a continuation of application Ser. No. 08/270,981, filed Jul. 5, 1994, now abandoned, which is a continuation of application Ser. No. 08/144,380, filed Nov. 2, 1993, now abandoned.

REFERENCE TO RELATED APPLICATIONS

The present application is related to the following U.S. patent application:

Ser. No. 08/144,378, titled "A MULTI-PROCESSOR DATA PROCESSING SYSTEM", filed Nov. 2, 1993, now U.S. Pat. No. 5,548,771, invented by Jack R. Davis et al.

1. Field of the Invention

The present invention relates in general to a data processing system, and more particularly to a method and apparatus for providing bus protocol simulation in a data processing system.

2. Background of the Invention

Fuzzy logic, neural networks, and other parallel, array oriented applications are becoming very popular and important in data processing. Most digital data processing systems today have not been designed with fuzzy logic, neural networks, and other parallel, array oriented applications specifically in mind. Thus there are considerable performance and cost benefits to be gained in designing digital data processing systems which are especially adapted and designed to meet the requirements of fuzzy logic, neural networks, and other parallel, array oriented applications.

SUMMARY OF THE INVENTION

The previously mentioned needs are fulfilled and other advantages achieved with the present invention. In one form, the present invention is a method for transferring data in a data processing system.

In one embodiment, the data processing system has a plurality of processors and an interface circuit. The plurality of processors is arranged in an array, and the interface circuit has a memory. The method includes the step of storing a first value in the memory. The first value has a control portion and has a data portion. The first value corresponds to a first address. The method includes the step of storing a second value in the memory. The second value has a control portion and has a data portion. The second value corresponds to a second address. The method includes the step of storing a third value in the memory. The third value has a control portion and has a data portion. The third value corresponds to a third address.

The method includes the step of receiving the first address by the memory; the step of retrieving the first value in response to the step of receiving the first address; and the step of transferring the control portion of the first value from the memory to a control circuit. If the control portion of the first value has a first state, the method includes the step of initiating a first data transfer between the memory and the array.

The method includes the step of receiving the second address by the memory; the step of retrieving the second value in response to the step of receiving the second address; and the step of transferring the data portion of the second value to the array during the first data transfer. If the control portion of the second value has the first state, the method includes the step of initiating a second data transfer between the memory and the array.

The method includes the step of receiving the third address by the memory; the step of retrieving the third value in response to the step of receiving the third address; and the step of transferring the data portion of the third value to the array during the second data transfer.

In an alternate embodiment, the present invention is a data processing system which has a first data bus, a second data bus, a control bus, a plurality of processors, and an interface circuit for providing bus protocol simulation. The interface circuit has a first memory circuit which is coupled to the first data bus and to the second data bus. The first memory circuit stores a first value which has a control portion and a data portion. The first memory circuit stores a second value which has a control portion and a data portion.

The interface circuit also has a second memory circuit which is coupled to the first data bus and to the second data bus. The second memory circuit stores a third value which has a control portion and a data portion. The second memory circuit stores a fourth value which has a control portion and a data portion. The interface circuit also has a first control circuit for providing a first control signal to a first one of the plurality of processors. The first control circuit asserts the first control signal to initiate transfer of the data portion of the second value if the control portion of the first value is a predetermined value. The first control circuit being coupled to the control bus, to the first memory circuit, and to the first one of the plurality of processors.

The interface circuit also has a second control circuit for providing a second control signal to a second one of the plurality of processors. The second control circuit asserts the second control signal to initiate transfer of the data portion of the fourth value if the control portion of the third value is the predetermined value. The second control circuit is coupled to the control bus, to the second memory circuit, and to the second one of the plurality of processors. The first control signal and the second control signal are asserted concurrently.

The present invention will be understood by one skilled in the art from the detailed description below in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates, in block diagram form, a data processing system 10 in accordance with one embodiment of the present invention;

FIG. 2 illustrates, in block diagram form, an array of processors (AEs) of FIG. 1 in accordance with one embodiment of the present invention;

FIG. 3 illustrates, in block diagram form, an edge interface of FIG. 1 in accordance with one embodiment of the present invention;

FIG. 4 illustrates, in block diagram form, bus protocol simulation logic (BPS) of FIG. 3 in accordance with one embodiment of the present invention;

FIG. 5 illustrates, in block diagram form, a portion of data processing system 10 of FIG. 1;

FIG. 6 illustrates, in block diagram form, a bus interface controller (BIC) of FIG. 1 in accordance with one embodiment of the present invention;

FIG. 7 illustrates, in block diagram form, a portion of the bus interface controller (BIC), the control bus, and the data bus of FIG. 6 in accordance with one embodiment of the present invention;

FIG. 8 illustrates, in block diagram form, a system memory of FIG. 1 in accordance with one embodiment of the present invention;

FIG. 9 illustrates, in block diagram form, a data processing system 210 in accordance with one embodiment of the present invention;

FIG. 10 illustrates, in block diagram form, an array of processors (AEs) of FIG. 9 in accordance with one embodiment of the present invention;

FIG. 11 illustrates, in block diagram form, an edge interface of FIG. 9 in accordance with one embodiment of the present invention;

FIG. 12-1 illustrates, in block diagram form, bus protocol simulation logic (BPS) of FIG. 11 in accordance with one embodiment of the present invention;

FIG. 12-2 illustrates, in block diagram form, a portion of memory 290 of FIG. 12-1 in accordance with one embodiment of the present invention;

FIG. 12-3 illustrates, in block diagram form, a transpose data movement pattern in accordance with one embodiment of the present invention;

FIG. 12-4 illustrates, in block diagram form, a ping-pong data movement pattern in accordance with one embodiment of the present invention;

FIG. 12-5 illustrates, in block diagram form, a checkerboard data movement pattern in accordance with one embodiment of the present invention;

FIGS. 13 through 30 illustrate, in schematic diagram form, a data processing system 10 of FIG. I in accordance with one embodiment of the present invention;

FIGS. 31-A-31-G illustrate, in tabular form, a parts list for the schematic diagram of data processing system 10 of FIGS. 13 through 30 in accordance with one embodiment of the present invention;

FIGS. 32 through 49-2 illustrate, in schematic diagram form, a data processing system 210 of FIG. 9 in accordance with one embodiment Of the present invention; and

FIG. 50-A-50-G illustrate, in tabular form, a parts list for the schematic diagram of data processing system 210 of FIGS. 32 through 49-2 in accordance with one embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The term "bus" will be used to refer to a plurality of signals or conductors which may be used to transfer one or more various types of information, such as data, addresses, control, or status. The terms "assert" and "negate" will be used when referring to the rendering of a signal, status bit, or similar apparatus into its logically true or logically false state, respectively. If the logically true state is a logic level one, the logically false state will be a logic level zero. And if the logically true state is a logic level zero, the logically false state will be a logic level one. The symbol "%" preceding a number indicates that the number is represented in its binary or base two form. The symbol "$" preceding a number indicates that the number is represented in its hexadecimal or base sixteen form.

FIGS. 1 through 8 illustrate a high level block diagram of one embodiment of data processing system 10. For more detail, refer to the complete board level schematic of data processing system 10 illustrated in FIGS. 13 through 31-2. FIGS. 9 through 12-2 illustrate a high level block diagram of one embodiment of data processing system 210. For more detail, refer to the complete board level schematic of data processing system 210 illustrated in FIGS. 32 through 50-2.

FIG. 1 illustrates one embodiment of a data processing system 10. Data processing system 10 has an Association Engine (AE) array 12, an edge interface circuit 14, an edge interface circuit 16, a switch circuit 18, a daughter board electrical connector 20, a system memory circuit 24, a host computer 28 coupled to a bus interface controller (BIC) circuit 22 by way of serial interface 40, and a host computer 30 coupled to a small computer system interface (SCSI) circuit 26 by way of SCSI connector 42.

The north and west ports of the AE array 12 are coupled to a control bus 36, an address bus 34, and a daughter board connector 20. Edge interface 14 is bi-directionally coupled to the south port of AE array 12. Edge interface 16 is bi-directionally coupled to the east port of AE array 12. Edge interface 14 is bi-directionally coupled to data bus 32 and to control bus 36, and is coupled to receive information from address bus 34. Edge interface 16 is bi-directionally coupled to data bus 32 and to control bus 36, and is coupled to receive information from address bus 34. Daughter board connector 20 is bi-directionally coupled to daughter board bus (DB bus) 38 and to control bus 36.

Bus interface controller 22 is bi-directionally coupled to data bus 32, address bus 34, and control bus 36. System memory 24 is bi-directionally coupled to data bus 32, and is coupled to receive information from address bus 34 and control bus 36. The SCSI circuit 26 is bi-directionally coupled to data bus 32, address bus 34, and control bus 36. Switch 18 receives control information from control bus 36, receives data from edge interface 14, and provides information to edge interface 16.

Host computer 30 includes a hard disk drive with a SCSI interface (not shown). In an alternate embodiment of the present invention, bus interface controller 22 and SCSI circuit 26 may be coupled to the same host computer 30. In yet other embodiments of the present invention, only one of host computer 28 and host computer 30 may be present.

In one embodiment of the present invention, bus interface controller 22 is a data processor which is capable of executing software instructions. The software instructions are used to control the transfer of information across the data bus 32, the address bus 34, and the control bus 36. Instructions and/or data may be downloaded to the bus interface controller 22 from the host computer 28 by way of serial interface 40. Data may then be transferred back to the host computer 28 from the bus interface controller 22 by way of the serial interface 40. The system memory 24 may be used to store software instructions and/or data. The SCSI circuit 26 may be used to transfer software instructions and/or data from the host computer 30 by way of SCSI connector 42. Data may then be transferred back to the host computer 30 from the SCSI circuit 26 by way of the SCSI connector 42.

Daughter board connector 20 may be used to input and output data to and from a daughter board (not shown). The configuration of the optional daughter board will be determined by the particular application in which data processing system 10 is being used. Edge interfaces 14 and 16 provide the ability to interface two different bus types operating at potentially different frequencies. The AE array 12 requires a particular bus protocol in order to communicate information between the AE array 12 and the edge interfaces 14 and 16. The data bus 32, the address bus 34, and the control bus 36 require a different protocol from the AE array 12 in order to communicate information between the busses 32, 34, and 36 and the edge interfaces 14 and 16. The edge interfaces 14 and 16 therefore must be able to communicate using the two different bus protocols.

FIG. 2 illustrates one embodiment of an array of processors (AEs) 12 of FIG. 1. Each Association Engine integrated circuit 50-65 is merely one embodiment of a data processor which may be used to form array 12. Other data processors may be used to form array 12 in FIG. 1. A detailed description of the structure and operation of the Association Engine data processor is described in a related, copending application entitled "A Data Processing System And Method Thereof", invented by Michael G. Gallup et al., having Ser. No. 08/040,779, filed Mar. 31, 1993, and assigned to the assignee hereof, which is expressly incorporated by this reference.

The combined north ports of AE processors 50-53 form a north array port of AE array 12. The combined south ports of AE processors 62-65 form a south array port of AE array 12. The combined west ports of AE processors 50, 54, 58, and 62 form a west array port of AE array 12. The combined east ports of AE processors 53, 57, 61, and 65 form an east array port of AE array 12. Although the illustrated embodiment of AE array 12 illustrates a four column by four row array of AE processors 50-65, an alternate embodiment of the present invention may use any number of rows and any number of columns.

Note that each AE processor 50-65 provides a busy signal, BUSY (not shown), and an interrupt signal, INTR (not shown), to the edge interfaces 14 and 16. The busy signal and the interrupt signal are not wire-ORed together. Also, each AE processor 50-65 has an enable pin, EN (not shown), all of which are wired-ORed together and coupled to edge interfaces 14 and 16. Each AE processor 50-65 has an access type pin, OP (not shown), all of which are wired-ORed together and coupled to edge interfaces 14 and 16. Each AE processor 50-65 has a read/write control pin, R/W (not shown), all of which are wired-ORed together and coupled to edge interfaces 14 and 16. And each AE processor 50-65 has a run/stop pin, R/S (not shown), all of which are wired-ORed together and coupled to edge interfaces 14 and 16.

FIG. 3 illustrates one embodiment of edge interface circuits 14 and 16 of FIG. 1. Edge interface circuits 14 and 16 each have bus protocol simulation logic circuits 70-73, address generator circuit 74, duration counter circuit 76, buffer circuit 78-81, and high speed address bus 82, which are coupled as illustrated in FIG. 3. Note that the term "X" in signal names "XCI" and "XCO" is used as a variable. For edge interface 14, which is coupled to the south array port, "XCI" represents "SCI", and for edge interface 16, which is coupled to the east array port, "XCI" represent "ECI". Likewise, for edge interface 14, which is coupled to the south array port, "XCO" represents "SCO", and for edge interface 16, which is coupled to the east array port, "XCO" represent "ECO". Also note that in one embodiment of the present invention, the "XCI" and "XCO" signals are active low.

FIG. 4 illustrates one embodiment of bus protocol simulation logic circuits 70-73 of FIG. 3. Bus protocol simulation logic circuits 70-73 each have a memory circuit 90, a programmable logic device circuit (PLD) 92, a host address buffer circuit 94, a host data transceiver circuit 96, and an AE transceiver circuit 98, which are coupled as illustrated in FIG. 4. Note that in one embodiment of the present invention, the memory 90 is a byte wide memory storing data bits 0:7!, which is the same width as the data path between each AE processor 50-65. Note that each bus protocol simulation logic circuit 70-73 is coupled to one port of a corresponding one of the AE processors 50-65.

FIG. 5 illustrates one embodiment of switch 18 of FIG. 1. Switch 18 has a plurality of transpose buffer circuits 100-103, which are coupled to edge interface 14 and edge interface 16.

FIG. 6 illustrates one embodiment of bus interface controller 22 of FIG. 1. Bus interface controller 22 has a programmable logic circuit 110, a control processor 112, a decoder array 114, and a plurality of registers, including other registers 116, busy status register 118, busy mask register 120, and comparator 122, which are coupled as illustrated in FIG. 6.

FIG. 7 illustrates one embodiment of a portion of bus interface controller 22 of FIG. 6. Busy mask register 120 stores a plurality of busy mask bits 0:15!. Each AE processor 50-65 provides one busy signal to comparator 122. If the busy mask bit for the corresponding AE processor 50-65 is negated, then the busy signal for that AE processor 50-65 is excluded from the comparison. Comparator 122 compares the non-excluded busy signals and asserts the global done output signal when all non-excluded busy signals have been negated, indicating that all of the non-excluded AE processors have completed operation.

FIG. 8 illustrates one embodiment of system memory 24 of FIG. 1. In one embodiment, system memory 24 is implemented using an EEPROM (Electrically Erasable Programmable Read Only Memory) 126, and a SRAM (Static Random Access Memory). Alternate embodiments of the present invention may use any type of memory for system memory 24.

FIGS. 9 through 12-2 illustrate a high level block diagram of one embodiment of data processing system 210. For more detail, refer to the complete board level schematic of data processing system 210 illustrated in FIGS. 32 through 50-2.

FIG. 9 illustrates one embodiment of a data processing system 210. Data processing system 210 has an Association Engine (AE) array 212, an edge interface circuit 214, an edge interface circuit 215, an edge interface circuit 216, an edge interface circuit 217, a host computer interface logic circuit 244, a host computer connector 246, and a host computer 248.

Edge interface 214 is bi-directionally coupled to the south port of AE array 212. Edge interface 215 is bi-directionally coupled to the north port of AE array 212. Edge interface 216 is bi-directionally coupled to the east port of AE array 212. And, edge interface 217 is bi-directionally coupled to the west port of AE array 212. Edge interface 214 is bi-directionally coupled to data bus 232 and to control bus 236, and is coupled to receive information from address bus 234. Edge interface 215 is bi-directionally coupled to data bus 232 and to control bus 236, and is coupled to receive information from address bus 234. Edge interface 216 is bi-directionally coupled to data bus 232 and to control bus 236, and is coupled to receive information from address bus 234. Edge interface 217 is bi-directionally coupled to data bus 232 and to control bus 236, and is coupled to receive information from address bus 234.

Host computer interface logic 244 is bi-directionally coupled to data bus 232 and control bus 236, and is coupled to provide information to address bus 234. Host computer interface logic 244 is bi-directionally coupled to host computer connector 246. Host computer connector 246 is bi-directionally coupled to host computer 248.

FIG. 10 illustrates one embodiment of an array of processors (AEs) 212 of FIG. 9. Each Association Engine integrated circuit 250-258 is merely one embodiment of a data processor which may be used to form array 212. Other data processors may be used to form array 212 in FIG. 9. Although the illustrated embodiment of AE array 212 illustrates a three column by three row array of AE processors 250-258, an alternate embodiment of the present invention may use any number of rows and any number of columns.

The combined north ports of AE processors 250-252 form a north array port of AE array 212. The combined south ports of AE processors 256-258 form a south array port of AE array 212. The combined west ports of AE processors 250, 253, and 256 form a west array port of AE array 212. The combined east ports of AE processors 252, 255, and 258 form an east array port of AE array 212.

FIG. 11 illustrates one embodiment of edge interface circuits 214-217 of FIG. 9. Edge interface circuits 214-217 each have bus protocol simulation logic circuits 270-272, address generator circuit 274, duration counter circuit 276, buffer circuit 278-280, and high speed address bus 282, which are coupled as illustrated in FIG. 11. Note that the term "X" in signal names "XCI" and "XCO" is used as a variable. For example, for edge interface 214, which is coupled to the south array port, "XCI" represents "SCI", and "XCO" represents "SCO".

FIG. 12-1 illustrates one embodiment of bus protocol simulation logic circuits 270-272 of FIG. 11. Bus protocol simulation logic circuits 270-272 each have a memory circuit 290, a programmable logic device circuit (PLD) 292, a host address buffer circuit 294, a host data transceiver circuit 296, and an AE transceiver circuit 928, which are coupled as illustrated in FIG. 12-1. Note that each bus protocol simulation logic circuit 70-73 is coupled to one port of a corresponding one of the AE processors 50-65.

Note that in one embodiment of the present invention, the memory 290 is a 9-bit wide memory storing data bits 0:8!, which is one bit more than the width of the data path between each AE processor 250-258. The extra bit is provided to programmable logic device 292. The programmable logic device 292 uses the extra bit as a control bit which is used to determine whether to assert or negate the "XCI" signal provided to the "XCI" input integrated circuit pin of the corresponding AE processor 250-258. Each location in memory 290 has a control portion 291 and a data portion 293. Although the control portion 291 in the illustrated embodiment of the present invention is one bit, alternate embodiments of the present invention may have a plurality of bits in the control portion 291. And although the data portion 293 is illustrated in FIG. 12-1 as having eight bits, alternate embodiments of the present invention may use any number of bits.

FIG. 12-2 illustrates one embodiment of a portion of memory 290 of FIG. 12-1. It is important to remember that data processing system 210 includes a plurality of memories 290. Data bit-8, labeled "D8", stores a single control bit which is provided to programmable logic device 292. In one embodiment of the present invention, programmable logic device 292 determines the proper timing and the proper conditions to allow the control bit D8 to be provided to the "XCI" input of the corresponding AE processor 250-258. When the proper conditions have been met, the programmable logic device 292 does not affect the value of the control bit D8 which is transferred to the corresponding AE processor 250-258.

Due to the bus protocol and timing required by the AE processors 250-258, the control bit 138 in address location "N" is associated with the data bits 130-137 in address location "N+1". For example, the control bit %0 in address location $X00 is associated with the data value $21 in address location $X01. When the control bit D8 in address location "N" is asserted, the data bits D0-D7 in the address location "N+1" are transferred, at the proper time, from memory 290 to the data input integrated circuit pins of the corresponding AE processor 250-258 by way of AE transceiver 298. Note that the term "X" in addresses $X00 through $X09 is used as a variable indicating that the address space $X00 through $X09 may be located at any convenient location in a memory map.

As an example, in one embodiment of the present invention, %0 is the negated state of the control bit D8, %1 is the asserted state of the control bit D8, memory 290 is coupled to AE processor 250, and memory 290 stores the values as indicated in FIG. 12-2. The data value $20 in address location $X00 is not used. Control bit D8 from address location $X00 is transferred to programmable logic device 292. Because the control bit is %0, no transfer is initiated by the programmable logic device 292 and the data value $21 in address location $X01 is not used. Next, control bit 138 from address location $X01 is transferred to programmable logic device 292. Because the control bit is %0, no transfer is initiated by the programmable logic device 292 and the data value $22. in address location $X02 is not used.

Next, control bit D8 from address location $X02 is transferred to programmable logic device 292. Because the control bit is %1, a transfer is initiated by the programmable logic device 292. On a first bus cycle, the programmable logic device 292 asserts the XCI signal provided to the AE processor 250. On the second bus cycle, the data value $23 from address location $X03 is transferred to AE processor 250. Control bits within each AE processor 250, 253, and 256 determine the movement of the data value $23 through the processor array 212. Each AE processor, if it receives the data value $23, has the choice of either storing or not storing the data value. In addition, each AE processor, if it receives the data value $23, has the choice of whether or not to pass the data value $23 on, and if so, in which direction.

Note that one bus cycle is required to transfer a data value from one AE port to the opposite AE port. For example, if AE processor 250 receives the data value $23 during the second bus cycle, then AE processor 250, if configured appropriately, can provide the data value $23 at the south port during the third bus cycle. And if AE processor 253 receives the data value $23 during the third bus cycle, then AE processor 253, if configured appropriately, can provide the data value $23 at the south port during the fourth bus cycle.

Also during the second bus cycle, control bit D8 from address location $X03 is transferred to programmable logic device 292. Because the control bit is %1, a transfer is initiated by the programmable logic device 292. On the second bus cycle, the programmable logic device 292 asserts the XCI signal provided to the AE processor 250. On the third bus cycle, the data value $24 from address location $X04 is transferred to AE processor 250. Control bits within each AE processor 250, 253, and 256 determine the movement of the data value $24 through the processor array 212. Each AE processor, if it receives the data value $24, has the choice of either storing or not storing the data value. In addition, each AE processor, if it receives the data value $24, has the choice of whether or not to pass the data value $24 on, and if so, in which direction.

Again, one bus cycle is required to transfer a data value from one AE port to another AE port. For example, if AE processor 250 receives the data value $24 during the third bus cycle, then AE processor 250, if configured appropriately, can provide the data value $24 at the south port during the fourth bus cycle. And if AE processor 253 receives the data value $24 during the fourth bus cycle, then AE processor 253, if configured appropriately, can provide the data value $24 at the south port during the fifth bus cycle. Note that by storing the asserted value "1" of the control bit D8 in consecutive address locations, data can be streamed into the AE processors (e.g. AE processors 250, 253, and 256) which are in the same row or column as corresponds to the memory 290. And by storing the negated value "0" of the control bit D8 in an address location, a break can be made in the stream of data be transferred to the AE processors (e.g. AE processors 250, 253, and 256) which are in the same row or column as corresponds to the memory 290.

Various methods for transferring data in data processing system 10 will now be discussed. Note that in some embodiments of the present invention, the tap and switch circuitry (not shown) in each AE processor 50-65 may be programmed to modify the data movement among the AE processors 50-65 in the AE array 12.

FIG. 12-3 illustrates a transpose data movement pattern using data processing system 10. Although the transpose data movement pattern is illustrated using data processing system 10, the transpose data movement pattern may be used to transfer data on other data processing systems. The transpose data movement pattern is especially useful for performing matrix computations which require a transpose operation. In one embodiment of the present invention, the matrix operations may involve one or more matrices of data stored in the Coefficient Memory Arrays (CMAs) (not shown) of the AE processors 50-65. In the example illustrated in FIG. 12-3, data is transferred out of the south array port of AE array 12 and into the east array port of AE array 12.

An example of the transpose data movement pattern will now be discussed. A data value is stored in each of AE processors 62-65. The data value stored in AE processor 62 is transferred to and stored in a corresponding memory 90, the data value stored in AE processor 63 is transferred to and stored in a corresponding memory 90, the data value stored in AE processor 64 is transferred to and stored in a corresponding memory 90, and the data value stored in AE processor 65 is transferred to and stored in a corresponding memory 90. The corresponding memories 90 are located in interface circuit 14 (see FIGS. 3 and 4). In one embodiment of the present invention, each time that the four data values from each of the processor 62-65 are transferred, they are transferred in parallel.

From the corresponding memories 90, the four data values are transferred to the transpose buffers 100-103 in switch 18 (see FIG. 5). The data value from AE processor 62 is transferred to transpose buffer 100, from transpose buffer 100 to interface circuit 16, and from interface circuit 16 to AE processor 65 where it is stored. The data value from AE processor 63 is transferred to transpose buffer 101, from transpose buffer 101 to interface circuit 16, and from interface circuit 16 to AE processor 61 where it is stored. The data value from AE processor 64 is transferred to transpose buffer 102, from transpose buffer 102 to interface circuit 16, and from interface circuit 16 to AE processor 57 where it is stored. The data value from AE processor 65 is transferred to transpose buffer 103, from transpose buffer 103 to interface circuit 16, and from interface circuit 16 to AE processor 53 where it is stored.

In alternate embodiments of the present invention, the data values may be stored in more, fewer, and different circuits as they are transferred. The bus interface controller 22 (see FIG. 1) is used to select and control the transpose data movement pattern by way of control bus 36.

FIG. 12-4 illustrates a ping-pong data movement pattern using data processing system 10. Although the ping-pong data movement pattern is illustrated using data processing system 10, the ping-pong data movement pattern may be used to transfer data on other data processing systems. The ping-pong data movement pattern is especially useful for quickly transferring a significant amount of data between the AE array 12 and the host processor 30.

An example of the ping-pong data movement pattern will now be discussed. A plurality of data values is stored in host computer 30. In one embodiment of the present invention, a large number of data values are stored on a hard disk drive of computer 30. The SCSI circuit 26 controls the transfer of data from the host computer to the memories 90 in edge interfaces 14 and 16.

A first set of data values are transferred from host computer 30 to the memories 90 in edge interface 14 by way of SCSI connector 42, SCSI circuit 26, and data bus 32. Then while the AE processors 50-65 are receiving and optionally storing the first set of data values from edge interface 14, a second set of data values are transferred from host computer 30 to the memories 90 in edge interface 16 by way of SCSI connector 42, SCSI circuit 26, and data bus 32. Then while the AE processors 50-65 are receiving and optionally storing the second set of data values from edge interface 16, a third set of data values are transferred from host computer 30 to the memories 90 in edge interface 14 by way of SCSI connector 42, SCSI circuit 26, and data bus 32. Note that a set of data values may include one or more bytes of data. Note also that each memory 90 in edge interface 14 may receive data at the same time in parallel, and may likewise provide data at the same time in parallel.

Thus using the ping-pong data movement pattern, the SCSI circuit 26 alternates between transferring data to/from edge interface 14 and to/from edge interface 16. Likewise, the AE array 12 alternates between transferring data to/from edge interface 14 and to/from edge interface 16. However, when the SCSI circuit is transferring data to/from edge interface 14, the AE array 12 is transferring data to/from edge interface circuit 16; and when the SCSI circuit is transferring data to/from edge interface 16, the AE array 12 is transferring data to/from edge interface circuit 14. The bus interface controller 22 (see FIG. 1) is used to select the ping-pong data movement pattern; however, the SCSI circuit 26 controls the actual data transfer once the ping-pong data movement pattern has been selected and initiated by the bus interface controller 22.

FIG. 12-5 illustrates a checkerboard data movement pattern using data processing system 10. Although the checkerboard data movement pattern is illustrated using data processing system 10, the checkerboard data movement pattern may be used to transfer data on other data processing systems. The checkerboard data movement pattern is especially useful in allowing both edge interfaces 14 and 16 to bunt data to the AE array 12. In other words, Stream Accesses, in Host Mode, can be made simultaneously in the south-to-north direction, and in the east-to-west direction.

An example of the checkerboard data movement pattern will now be discussed. The bus interface controller 22 (see FIG. 1) is used to select and control the checkerboard data movement pattern by way of control bus 36. The bus interface controller 22 must cause the proper control values to be stored in the appropriate control bits of each AE processor 50-65 in order to permit the checkerboard data movement pattern to be used. The bus interface controller 22 selects all rows and all columns in AE array 12 by asserting both the row integrated circuit pin ROW and the column integrated circuit pin COL of each All processor 50-65. The bus interface controller 22 also configures each AE processor 50-65 to be in Host Stream Mode. In addition, the bus interface controller 22 must cause the appropriate values to be stored in the Host Stream Select Port bits (HSP 1:0!) in each AE processor 50-65

Note that in Host Stream Mode, the AE processors 50-65 can receive and store data, can pass on data without storing, and can act as the original source of data. The Host Stream Select Port bits (HSP 1:0!) (not shown) in each AE processor 50-65 determine the movement of the data through the processor array 212. For write accesses, each AE processor receives a data value, and based upon the value of the HSP control bits, has the choice of either storing or not storing the data value before passing on the data value. For read accesses, the HSP control bits in each AE processor 50-65 determine whether that particular processor acts as an original source of the data value, or merely passes on the data value. Note that the checkerboard data movement pattern allows data to be transferred between AE processors 50-65 in the west-to-east direction and the north-to-south direction concurrently.

In the example illustrated in FIG. 12-5, the AE processors which are cross-hatched, namely 51, 53, 54, 56, 59, 61, 62, and 64 all have a %10 stored in the Host Stream Select Port bits (i.e. HSP control bits) and thus transfer data out the east port. On the other hand, the AE processors which are not cross-hatched, namely 50, 52, 55, 57, 58, 60, 63, and 65, all have a %01 stored in the HSP control bits and thus transfer data out the south port.

As an example, for north-to-south data movement, a data value sourced by AE processor 50 would be transferred to AE processor 54, then AE processor 58, then AE processor 62, and then finally to interface circuit 14 (i.e. memory 90 coupled to AE processor 62). A data value sourced by AE processor 55 would be transferred to AE processor 59, then AE processor 63, and then finally to interface circuit 14 (i.e. memory 90 coupled to AE processor 63). For west-to-east data movement, a data value sourced by AB processor 51 would be transferred to AE processor 52, then AE processor 53, and then finally to interface circuit 16 (i.e. memory 90 coupled to AE processor 53). A data value sourced by AE processor 54 would be transferred to AB processor 55, then AE processor 56, then AE processor 57, and then finally to interface circuit 16 (i.e. memory 90 coupled to AE processor 57). The above example is an example of a fine-grain checkerboard data movement pattern.

The present invention may also be used to perform a coarse-grain checkerboard data movement pattern. As an example, AE processors 50-51, 54-55, 60-61, and 64-65 may all have a %10 stored in the Host Stream Select Port bits (i.e. HSP control bits) and thus may transfer data out the east port. On the other hand, the AE processors 52-53, 56-59, and 62-63 may all have a %01 stored in the HSP control bits and may thus transfer data out the south port.

For west-to-east data movement, a data value sourced by AE processor 50 would be transferred to AE processor 51, then AE processor 52, then AE processor 53, and then finally to interface circuit 16 (i.e. memory 90 coupled to AE processor 53). A data value sourced by AE processor 51 would be transferred to AE processor 52, then AE processor 53, and then finally to interface circuit 16 (i.e. memory 90 coupled to AE processor 53). For north-to-south data movement, a data value sourced by AE processor 52 would be transferred to AE processor 56, then AE processor 60, then AE processor 64, and then finally to interface circuit 14 (i.e. memory 90 coupled to AE processor 64). A data value sourced by AE processor 56 would be transferred to AE processor 60, then AE processor 64, and then finally to interface circuit 14 (i.e. memory 90 coupled to AE processor 64).

The checkerboard data movement pattern thus allows data to be transferred from the AE array 12 to interface circuit 14 at the same time that data is being transferred from the AE array 12 to interface circuit 16. Note that the Host Stream Select Port bits (i.e. HSP control bits) in each AE processor 50-65 also determine whether the AE processor 50-65 sources and passes data, or merely passes data. In one embodiment of the present invention, if the HSP control bits are either %01 or %10, the AE processor 50-65 both sources and passes on data. However, if the HSP control bits are either %00 or %11, the AE processor 50-65 does not source data, but merely passes on data.

Note that more than one AE processor 50-65 in a column and more than one AE processor 50-65 in a row may source data. For example, in the fine-grain checkerboard data movement pattern illustrated in FIG. 12-5, AE processors 52 and 60 both have a %01 stored in the HSP control bits and thus source data out the south port. AE processor 52 sources data first, while AE processors 56, 60, and 64 merely pass on the data sourced by AE processor 52. Then when AE processor 52 has finished sending data, AE processor 60 sources data, while AE processor 64 merely pass on the data sourced by AE processor 60.

While the present invention has been illustrated and described with reference to specific embodiments, further modifications and improvements will occur to those skilled in the art. It is to be understood, therefore, that this invention is not limited to the particular forms illustrated and that it is intended in the appended claims to cover all modifications that do not depart from the spirit and scope of this invention. 

We claim:
 1. A method for transferring data in a data processing system, the data processing system comprising a plurality of processors and an interface circuit, the plurality of processors being arranged in an array, and the interface circuit having a memory, the method comprising the steps of:storing a first value in the memory, the first value having a control portion and having a data portion, the first value corresponding to a first address location; storing a second value in the memory, the second value having a control portion and having a data portion, the second value corresponding to a second address location; storing a third value in the memory, the third value having a control portion and having a data portion, the third value corresponding to a third address location; retrieving the first value from the first address location in the memory and transferring the control portion of the first value from the memory to a control circuit; if the control portion of the first value has a first state, initiating a first data transfer between the memory and the array; retrieving the second value from the second address location in the memory and transferring the data portion of the second value to the array during the first data transfer; if the control portion of the second value has the first state, initiating a second data transfer between the memory and the array; and retrieving the third value from the third address location in the memory and transferring the data portion of the third value to the array during the second data transfer.
 2. A method as in claim 1, wherein the control portion of the first value is a single control bit.
 3. A method as in claim 1, further comprising the steps of:transferring a first address corresponding to the first address location from an address generator circuit to the memory; transferring the control portion of the first value from the memory to the control circuit; and if the control portion of the first value has the first state, asserting a control signal provided to a first one of the plurality of processors.
 4. A method as in claim 3, further comprising the steps of:transferring a second address corresponding to the second address location from the address generator circuit to the memory; transferring the control portion of the second value from the memory to the control circuit; and if the control portion of the second value has the first state, continuing to assert the control signal provided to the first one of the plurality of processors.
 5. A method as in claim 4, further comprising the steps of:transferring a third address corresponding to the third address location from the address generator circuit to the memory; transferring the control portion of the third value from the memory to the control circuit; and if the control portion of the third value has a second state, negating the control signal provided to the first one of the plurality of processors.
 6. A method for transferring data in a multi-processor data processing system having a first processor, a second processor, and an interface circuit, the interface circuit having a memory, the method comprising the steps of:storing a first value in the memory, the first value having a control portion and having a data portion; storing a second value in the memory, the second value having a control portion and having a data portion; storing a third value in the memory, the third value having a control portion and having a data portion; accessing the first value in the memory; if the control portion of the first value has a predetermined state, providing a first data valid control signal from the interface circuit to the first processor during a first bus cycle; accessing the second value in the memory; if the control portion of the first value has the predetermined state, providing the data portion of the second value to the first processor during a second bus cycle; if the control portion of the second value has the predetermined state, providing the first data valid control signal from the interface circuit to the first processor during the second bus cycle; accessing the third value in the memory; and if the control portion of the second value has the predetermined state, providing the data portion of the third value to the first processor during a third bus cycle.
 7. A method as in claim 6, further comprising the step of:if the control portion of the first value has the predetermined state, providing a second data valid control signal from the first processor to the second processor during the second bus cycle.
 8. A method as in claim 7, further comprising the step of:if the control portion of the first value has the predetermined state, providing the data portion of the second value to the second processor during the third bus cycle.
 9. A method as in claim 6, further comprising the steps of:if the control portion of the first value has the predetermined state, and a control element in the first processor has selected a first control condition, storing the data portion of the second value in the first processor; and if the control portion of the first value has the predetermined state, and the control element in the first processor has selected a second control condition, inhibiting the storing of the data portion of the second value in the first processor.
 10. A method as in claim 9, further comprising the steps of:if the data portion of the second value is provided to the second processor, and a control element in the second processor has selected the first control condition, storing the data portion of the second value in the second processor; and if the data portion of the second value is provided to the second processor, and the control element in the second processor has selected the second control condition, inhibiting the storing of the data portion of the second value in the second processor.
 11. A data processing system, comprising:a data bus; an address bus for providing a first address and for providing a second address; a control bus; a plurality of processors; and a storage circuit, coupled to said data bus, said address bus, and said plurality of processors;wherein said storage circuit comprises: first memory means, accessed by the first address, for storing a control portion of a first value; second memory means, accessed by the first address, for storing a data portion of the first value; third memory means, accessed by the second address, for storing a control portion of a second value; and fourth memory means, accessed by the second address, for storing a data portion of the second value;wherein said data processing system further comprises: control means for receiving the control portion of the first value, in response to the control portion of the first value having a predetermined value said control means providing a control signal to a first one of said plurality of processors to initiate transfer of the data portion of the second value to the first one of the plurality of processors, said control means being coupled to said control bus, to said storage circuit, and to the first one of the plurality of processors.
 12. A data processing system as in claim 11, wherein the first control signal and the second control signal are asserted approximately concurrently. 